Securely Managing Environment Variables for Web Deployments

#!/bin/bash

# Configuration
# Define the base directory where your application's .env files reside
APP_ROOT="/var/www/your_app"

# Define the environment you want to load (e.g., 'development', 'staging', 'production')
# This can also be passed as an argument to the script: ./load_env.sh production
ENV_NAME="production"

# --- DO NOT EDIT BELOW THIS LINE ---

# Override ENV_NAME if provided as a command-line argument
if [ -n "$1" ]; then
    ENV_NAME="$1"
fi

ENV_FILE="${APP_ROOT}/.env.${ENV_NAME}"
DEFAULT_ENV_FILE="${APP_ROOT}/.env"

if [ ! -f "${ENV_FILE}" ]; then
    echo "Warning: Environment file '${ENV_FILE}' not found. Trying default '.env' file." >&2
    ENV_FILE="${DEFAULT_ENV_FILE}"
    if [ ! -f "${ENV_FILE}" ]; then
        echo "Error: Default environment file '${ENV_FILE}' not found either." >&2
        exit 1
    fi
fi

echo "Loading environment variables from: ${ENV_FILE}"

# Source the environment file
# This makes the variables available in the current shell context
set -a # Automatically export all variables subsequently defined
source "${ENV_FILE}"
set +a # Turn off auto-export

# Verify a variable (example)
# You might use this in a deployment script to ensure critical variables are loaded
if [ -z "$DB_HOST" ]; then
    echo "Warning: DB_HOST environment variable not set." >&2
else
    echo "DB_HOST is set to: ${DB_HOST}"
fi

# You can now run your application, and it will pick up these variables
# Example: /usr/bin/php ${APP_ROOT}/artisan migrate
# Example: npm start